This was one of my better flashlight laser mods in the early days. I recovered the details from my original post on Laser Pointer Formus.
ALWAYS WEAR 445nm RATED SAFETY GLASSES WHEN TESTING AND OPERATING THIS DEVICE. MOMENTARY EXPOSURE TO THE EYES CAN CAUSE PERMANENT EYE DAMAGE AND PROLONGED SKIN CONTACT CAN CAUSE BURNS!
Many of the parts for this build were sourced from a reputable laser forum Laser Pointer Forums. IF you are just getting started in lasers, it is a great place to gain knowledge. Some of people I recommend buying from/talking to are ARG and MrCrouse.
First we need to clear out the original C8 flashlight host to make way for all of the laser parts we will be installing. The reflector, LED, and circuit will all have to removed to make room for a large heatsink we will be installing to wick heat away from the laser diode.
The LED and original circuit are housed in what is called a "pill" and can be unscrewed and separated from the host.
This pill can be repurposed and used in the build but I picked up some brass pills from fasttech that had a little more room inside.
Now that the host is completely empty, we can start the build.
The driver circuit needs to receive input power from the battery (positive contact connects to the top of the battery on the bottom of the circuit board) by making contact with the positive side of the battery and receiving Ground from the host body (or "case"). Therefore this is a "case negative" build. Luckily, the diode is case neutral so we don't need to worry about this.
Also, the driver has a continuous ground so we don't have a separate ground output (this makes it easier).
So, I soldered a wire from the case (the brass pill) to the negative contact on the driver, and then added two output leads (positive output pad and ground pad)
After adding all the appropriate leads, I used thermal adhesive to attach a heatsink onto the main IC ont he driver to dissapate heat.
Now all that was left was to assemble the pill into a finished part. All that is required is to push the wires through the holes and glue the circuit in place. Hot glue is OK here, just dont use too much.
Finally I stripped the leads and tinned them with solder.
Now I had to prepare the diode assembly so that I could just connect the two pairs of wires and have a working handheld laser.
First I slid the 12mm module into the heatsink, countersunk it a few mm, and screwed in place with a small hex screw. Then, I installed the spring to keep the lens under tension and then I screwed in the G2 lens (with focus adapter to prevent finger burns).
Now I just cut the leads to a reasonable length, and cut off the white (neutral) wire as it was unneeded. Then, I stripped the wires and tinned them.
All that was left to do was solder the wires from the driver to the wires to the diode, and add heatshrink. Then carefully screwed the pill into the host whie taking care not the twist the wires too much.
After this I placed the heatsink/diode assembly into the flashlight host, and screwed the crown on. Make sure the heatsink does not turn with the crown when you are screwing it on.
After this you should be done! Put in 2 16340 Li-ion batteries, or one 18650 (depending on what driver you used) and press the tail switch. If the beam is not small like a dot it needs to be focused. Simply turn the lens on the front (dont burn yourself) to focus the laser beam to a dot (really a rectangle).
To burn things you can screw the lens all the way in, then focus to a dot, and then turn it a little farther to create a focus point about 6" to 14" away from the aperture. This is a point where the beam is extremely concentrated and even paper can be set on fire at this point.
NOTE ABOUT DUTY CYCLE: When using any high powered laser devices a duty cycle must be observed, as a 2 watt diode emmits a large ammount of heat as waste energy. If this is not taken into account the diode can overheat and die. For a host this size I recommend a maximum of 3 minutes on and 2 minutes off. If at any time the head of the laser is warm/hot to the touch turn off the device immediately.